Brush



INVENTOR.

arffzez' MXM f g m Z 8 1 1 BRUSH Filed April 19, 1947 Patented June 26, 1951 UNITED STATES PATENT OFFICE .BRUSH John G. Baumgartner, Oswego, Ill.

Application April 19, 1947, Serial No. 742,530

3 Claims.

This invention relates generally to brushes and in particular to a small brush adapted for use in applying lacquer and the like.

A divisional and continuing application on the machine and method of making such a brush was filed February 2, 1949, as Serial No. 74,106.

Brushes now commonly used in applying lacquer, such as for applying fingernail polish and for use in art work, include a small cylindrical handle into which are secured bristles normally made of pony or camel hair or other natural fiber. Such natural hairs and fibers are naturally not uniform in size and shape, and to provide a brush of high quality careful selection of the fibers is necessary. This requires a large amount of labor making the brush relatively exvide synthetic fibers very inexpensively, the prior brushes utilizing them have not been satisfactory for applying lacquer or similar coating material.

It is, therefore, an object of the present invention to provide an improved brush for applying lacquer having bristles made of synthetic fibers.

A further object of this invention is to provide a small inexpensive brush for applying lacquer such as nail polish, which will spread the lacquer over a surface evenly.

A feature of this invention is the provision of a brush having bristles made of synthetic fibers in which the ends of the bristles are of 2 generally pointed configuration.

Still another feature of this invention is the provision of a small brush having bristles which are of uniform size and which have suflicient stiffness to retain their normal uniform position without becoming tangled or matted.

A further feature of this invention is the prc vision of a fingernail polish brush including plastic handle having a diameter of the order of of an inch with an axial cavity approximatcy of an inch in diameter therein in which a tuft of bristles of synthetics fibers such as nylon is secured, the bristles having the outer ends there 7 of ground into a generally pointed configuration.

A still further feature of this invention is the provision of a small brush for applying lacquer including a tuft of synthetic fibers each having a diameter of the order of four-thousandths c an inch and having pointed ends with a taper of approximately 15 to 1.

Further objects, features and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawings in which:

Fig. 1 shows in actual size the complete assembly of the brush of this invention;

Fig. 2 illustrates the brush of Fig. 1 in assemled relation with a container for the liquid to be applied by the brush;

Fig. 3 is an enlarged longitudinal sectional view along the line 3-3 of Fig. 1;

Fig. 4 is an enlarged view showing the natural configuration of the ends of the bristles when out;

Fig. 5 is an enlarged view showing the configuration of the bristles after being ground.

In practicing my invention I provide a small brush suitable for applying lacquer such as nail polish which includes a plastic handle having a diameter of approximately of an inch and which has an axial cavity in one end thereof in which a tuft of bristles is secured. The tuft of bristles is of the order of of an inch in diameter and includes a plurality of bristles held in the cavity by a staple. The bristles are made of a synthetic fiber, such as nylon, and are of uniform size and are sufficiently stiff to prevent tangling and matting thereof when in use. The ends of the bristles are tapered by passing the bristles of a completed brush over a rotary grinding wheel and simultaneously turning the brush so that the bristles are uniformly ground.

Referring now to the drawings, the brush as illustrated in Fig. 1 includes a handle 10 which may be made of any suitable plastic material with a tuft of bristles ll secured in one end thereof and a finger gripping portion I2 secured to the other end. As illustrated in Fig. 2, the finger gripping portion l2 may also serve as a cap for a container I3 for the liquid to be applied by the brush.

Fig. 3 illustrates the details of the construction of the brush, illustrating the handle 10 as having an enlarged head portion l4 adapted to be tightly secured in a tubular projection IS on the finger gripping portion 12. The finger gripping portion may include threads l5 for engaging similar threads on the container l3 and a sealing washer I! so that a tight seal can be made thereby. The bottom end of the handle includes a cavity 18 which extends axially within the handle to a depth at least equal to the diameter of the handle. The bristle tuft H is receivable within the cavity on the ends thereof.

l8 and is secured directly to the handle H) by a staple l9 straddling the bristles in the tuft for anchoring the tuft at the bottom 29 of the cavity. This arrangement of securing the bristles in the handle is covered in my prior Patent No. 2,348,515.

The bristle tuft H is composed of a plurality of bristles 2| which are doubled back about the loop formed by the staple l9 as illustrated in Fig. 3. The tuft is of such diameter to fit tightly within the cavity [8 and is positioned in the cavity to such a depth that a relatively tight tuft of bristles is formed. The length of the tuft is approximately of an inch and the diameter of the bristles is of the order of four-thousandths of an inch forming a tuft which is readily yieldable. The outer ends of the bristles in the tuft are tapered as will be more fully explained.

As previously stated, the bristles are formed of synthetic fibers, nylon fibers having been found to be satisfactory for a nail polish brush. It is pointed out, however, that rayon or other synthetic fibers may be more suitable in other applications and accordingly it is not desired that the invention be limited to the use of nylon fibers.

The fibers are drawn to the desired diameter,

fibers having a diameter of approximately fourthousandths of an inch having been found particularly desirable for use in a small nail polish brush as illustrated. After the fibers are formed into a tuft and secured in the handle as illustrated in Fig. 3, the tuft must be finished in order to provide a brush which is suitable for applying lacquer or the like. The ends of the fibers are cut off squarely to form an even end on the tuft. It has been found that when the nylon fibers are cut off the ends thereof are enlarged or become mushroomed as is illustrated in Fig. 4. Microscopic photographs indicate that the ends are enlarged to the extent that the area thereof is more than twice the cross-sectional area of the fiber itself. Fig. 4 was made from a microscopic photograph of fibers approximately four-thousandths of an inch in diameter, the enlarged ends being illustrated at 22.

Although the tuft of bristles after having the ends thereof trimmed forms a brush having an even edge, it is apparent that the enlarged ends of the bristles will not permit lacquer or similar material to be spread smoothly as is required in the application of fingernail polish or as is required in art work or other application. It has been found, however, that if the nylon bristles are ground to provide ends which are of generally pointed configuration with a long taper, a brush having such bristles works very satisfactorily, being generally superior to high class pony or camel hair brushes. Fig. 5 is a greatly enlarged representation of the bristles, being taken from an actual microscopic photograph of bristles as shown in Fig. 4 after having the ends thereof ground. The grinding operation may be performed by moving the end of the tuft of an assembled brush over the face of a rotary grinding wheel. Fig. 5 illustrates bristles which have been ground to provide a taper of approximately 15 to 1 That is, the length of the taper is approximately 15 times as great as the diameter of the bristles since the bristles taper to a point. Bristles having a taper of 8 to 1 have been found to be satisfactory for a lacquer brush, but a longer taper is preferable. In addition to providing generally pointed ends on the fibers to provide a brush which will spread lacquer evenly, the grinding of the ends tends to roughen the surface of the fibers providing recesses which help to hold the lacquer on the bristles. 4

The tapered pointed ends on the bristles 2|, as shown in Figs. 3 and 5, are obtained by spread ing the bristle tuft of Fig. 3, fan-like against a rotating grinding wheel surface, and with the bristles inclined at an angle to such surface. The end portions of the bristles alone, are incontact with the Wheel surface. Then, during this grinding operation, the handle I0 of each brush is rotated by suitable mechanism so as to change the position of the bristles spread out on the grinding wheel surface. This turning of the handle of a brush, and the resulting change in position of the bristles on the rotating grinding wheel surface causes the bristles to be uniformly ground and tapered to a point.

In the grinding each bristle is in contact with f the grinding wheel for substantially the same period of time resulting in the tapers on the individual bristles being substantially identical so that the characteristics of the bristles, such as the resilience thereof, is substantially identical. It is obvious that the characteristics of the grinding wheel used, the-speed of operation of the grinding wheel, and the position and movement of the bristle tufts with respect to the grinding wheel will all affect the taper obtained on the bristles. I

Considering now the completed brush, as the synthetic fibers may be drawn to have a substantially constant diameter, the bristles of a brush using such fibers will be substantially completel uniform. For this reason the individual bristles are of very nearly the same flexibility so that when the brush is used the bristles will all be flexed to substantially the same extent and will spread out evenly in a uniform arc and not become tangled and matted. On the other hand, the natural hair bristles, even when carefully selected, will not be identical and the hairs will not have uniform resiliency with the result that the hairs become crossed and tangled. Also, the ends of the natural hair bristles will not be evenly tapered and not spread in an even uniform arc. The uniformity of synthetic bristles together with the uniformly tapered ends thereof results in a brush which will spread lacquer or similar material very evenly without forming ridges and lines on the surface being coated. As previously stated, such brushes have been found to be far superior to brushes made of pony or camel hair. It is seen from the above that I have provided a brush which is suitable for application of lacquer or similar coating material and which will provide very uniform application of such material and is at the same time very inexpensive. The handle is made of plastic material which may be very cheaply formed and the assembly of the tuft therein as described may be very readily and cheaply accomplished. The bristles being made of synthetic fibers are also very inexpensive and are clean thereby eliminating the cleaning operation required when processing natural hair. Also the nylon or synthetic fibers are much tougher and not subject to chemical deterioration as is natural hair. The brush, therefore, retains its desired characteristics for a much longer time resulting in a much longer life for the brush. It has further been found that the synthetic fiber bristles are much easier to clean than natural hair bristles.

Although one embodiment of my invention has been described which is illustrative thereof, it is apparent that various changes and modifications can be made therein which are within the intended scope of the invention as defined in the appended claims.

I claim:

1. A small synthetic fiber bristle brush for application of liquid thereby in an even smooth manner, including in combination a handle having a cavity in one end thereof, and a bristle tuft secured in said cavity and having a portion exposed beyond the brush handle, said bristle tuft comprising a plurality of synthetic fiber bristles, each bristle corresponding in diameter in the body portion and substantially all of said bristles having at the end thereof a substantially conical taper extending from the body-portion-diameter dimension to a sharp point at the outer end, the length of taper being greater than the diameter of the bristle at the body portion and said synthetic fiber bristles being substantially uniform in resiliency over the exposed length so that the tuft bends uniformly upon application of liquid thereby to a surface.

2. A small synthetic fiber bristle brush for application of liquid thereby in an even smooth manner, including in combination a handle approximately inch in diameter having a bristle tuft secured therein with a portion exposed beyond the brush handle, said bristle tuft comprising a plurality of synthetic fiber bristles, each bristle corresponding in diameter in the body portion thereof and substantially all of said bristles having at the end thereof a substantially conical taper extending to a sharp point at the outer end, each of such bristle tapers being abrasive-ground to the sharp point, the length of the conical and pointed taper on such bristles being greater in each instance than the body-portion diameter of the bristle, with said synthetic fiber bristles bending substantially uniformly over their exposed length upon the application of liquid thereby to a surface.

3. A small synthetic fiber bristle brush for application of liquid thereby in an even smooth manner, including in combination a handle approximately g inch in diameter having a cavity in one end thereof, and a bristle tuft rigidly secured in said cavity and having portion exposed beyond the handle, said bristle tuft comprising a plurality of synthetic fiber bristles corresponding in diameter in the body portion and substantially all of said bristles tapered at the liquid application end thereof from a grinding operation thereon in a substantially conical paper extending to a sharp point, said taper of a bristle having a ratio in the range from approximately 8 to l to 15 to 1 as between the diameter of a bristle and the length of the pointed taper on such a bristle, and said bristles having uniform resilience for uniform bending as a tuft upon application of the liquid thereby to a surface.

JOHN BAUMGAR'I'NER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,495,747 Izawa May 27, 1924 1,628,291 Weber May 10, 1927 2,227,126 Cooke Dec. 31, 1940 2,341,823 Smith Feb. 15, 1944 2,343,782 Lotters Mar. 7', 1944 2,348,515 Eaurngartner May 9, 1944 2,365,396 Cunningham Dec. 19, 1944 2,408,718 HauX Oct. 1, 1946 2,508,799 Reis May 23, 1950 2,511,004 Peterson June 18, 1950 

